This relates generally to imaging devices, and more particularly, to imaging devices with image sensor pixels.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an array of image pixels arranged in pixel rows and pixel columns.
To eliminate motion artifacts, global shutter CMOS (complementary metal-oxide semiconductor) image sensors incorporate a storage node between the photodiode and readout transistors. Unlike rolling shutter CMOS pixels, the start and end of integration in global shutter CMOS image sensors occur simultaneously for all pixels. Charge stored at the storage node are then readout using the standard rolling shutter method.
Many applications require high dynamic range (HDR) performance. One method for extending the dynamic range for rolling shutter pixels is to capture multiple images with different exposure times and then merge the images together post-capture to create an HDR image. Motion artifacts are a well-known issue with rolling shutter readout. The addition of multiple exposure times only exacerbates the motion artifacts.
It is within this context that the embodiments herein arise.